Pay digital content, such as audio and video files for example, is transmitted from a server to a client over a network, such as the Internet. In such a case, a client user is first authenticated to the server and the content is then transmitted in accordance with a protocol, such as FTP, HTTP and SSL.
Transmission of content, however, involves such security problems as unauthorized interception, tampering, masquerading, denial of a concluded transaction, redistribution and the like. To prevent such problems, it is proposed that a digital watermark be embedded in the content to restrict its ownership, or that the content be encrypted so that it cannot be replayed without a proper decryption key which can be obtained for value.
However, content encrypted in a particular encryption method can not necessarily be decrypted by any client or electronic apparatus. In addition, the content provider does not always desire to protect all kinds of items of content in the same security scheme. For example, the provider may want to transmit content of higher value in a higher security scheme, and to transmit content of lower value, or content such as advertisement content which is required to be distributed widely, in a lower security scheme without encryption.
In Japanese Unexamined Patent Publication 2001-325177 (A) published on Nov. 22, 2001, Miyazaki discloses a content application server. When the server receives apparatus specification environment information and a request for a content application from a client, the server converts a corresponding source content application to a content application which conforms to the apparatus specification environment information, and supplies the converted content application to the client.
In Japanese Unexamined Patent Publication 2001-202307 (A) published on Jul. 27, 2001, Kawamoto et al. discloses a method of communication between terminals over a network. In this method, one terminal distinguishes a communication application which can be used by another terminal, and transmits information to the other terminal by using that application.
In Japanese Unexamined Patent Publication 2001-175757 (A) published on Jun. 29, 2001, Yamanaka et al. disclose a system for delivering digital content over a network. In this system, a buyer transmits information describing desired content and a transfer condition to a seller. The seller delivers the described content to the buyer in accordance with the transfer condition.
In Japanese Unexamined Patent Publication HEI 11-341040 (A) published on Dec. 10, 1999, Saito et al. disclose a communication apparatus connected between two networks. The communications apparatus collects attribute information from a server on the first network, presents the server's attribute information to a terminal on the second network in accordance with the protocol of the second network, transmits to the server a request for the service selected in accordance with the attribute information, and provides the service from the server to the terminal, if necessary, by converting a format.
In Japanese Unexamined Patent Publication 2001-256162 (A) published on Sep. 21, 2001, Asai et al. discloses a portable terminal which acquires content from a server via a gateway. The content includes a file and an identifier indicating the type of a file, such as video, audio and the like. The terminal transmits the content file to a peripheral device corresponding to an identifier.
The inventors have recognized the need for selection of a security scheme for the transmission of content in accordance with a license policy of a content provider. The inventors have also recognized the need for the transmission or delivery of content from a server to a client in a security scheme available on the client.
An object of the present invention is to provide secure transmission of content to a buyer in accordance with a license policy of a content provider.
Another object of the present invention is to transmit content in an available secure transmission scheme to a user.